Internal frame backpacks, which have a frame structure integrated into the inside of the backpack, have been around for some time and are routinely used by hikers and mountaineers. The backpack frame may be lightweight yet strong enough to withstand the weight of the load as well as withstand being sat on or leaned up against, as can routinely happen during long and arduous expeditions. However, such frames are often rigid and thus provide no torsional flexibility to permit the backpack frame to flex and move along with the user.
In the past, backpack manufacturers have attempted to address this issue by designing frames or backpacks that permit a twisting motion or backward/forward motion. However, when the user hikes, especially on a incline or decline, the shoulders rotate and the spine bends forward and backward, while the hips rotate and move up and down with each step, thus producing more than a simple twisting or backward/forward motion. Since the backpack frame does not provide movement/flexibility to match the “dynamic motion” of the hiker, the user experiences strain, discomfort and fatigue as the user must use core muscles in the back and abdomen to stabilize the body and counteract the flopping/mismatched movement of the backpack. Thus, there remains a need for a backpack suspension system that allows “dynamic motion” to match that of the user's body motion. Embodiments of the present invention fulfill this need.